Desk lamps are widely used by designers and students. Since a desk lamp is used to write words or to draw figures, the illuminating area is typically not large. The area illuminated by a desk lamp should be brighter than any area illuminated by a table lamp. Therefore, all prior art desk lamps have a reflector for converging projected light beams (from the bulb) into a relatively small area, and some desk lamps even have a lens for converging said convened light beams into an even smaller area. All prior desk lamps have typically been designed to illuminate the working area on the desk, but the main function of a desk lamp should be to help the user to write words or draw figures, and not only limited to providing illumination. Applicant has found no prior art desk lamp which has the function of helping the user to write words or to draw figures. For example, a student or designer always has a need to enlarge existing words or figures on a paper. If the words or figures can be projected (enlarged) onto the paper by the desk lamp with a predetermined ratio, he (or she) can easily outline the words or figures on the paper.
The principal optical components such as the light source (the bulb), the reflector and the lens may already exist in a conventional desk lamp. The additional projection function can be achieved with suitable modifications of the desk lamp. In addition, existing mechanical structure for a traditional desk lamp such as the base, the stem, the bracket, etc., can also fulfill the newly added optical function; no additional supporting structure should be added for this newly added optical function.